Some fire suppression systems use vapor pressure sealed within a container to expel a liquid fire suppressant from the container into a distribution manifold. The vapor pressure may be maintained by a propellant gas inside of the container and/or the fire suppressant itself. The fire suppressant may be expelled or released in response to receiving an input at a user interface, or in response to an alarm generated by a sensor such as a smoke detector or a heat sensor, for example. This conventional approach has some drawbacks.
Once the container is filled and sealed to contain the fire suppressant and/or the propellant gas, these liquids and/or vapors are typically stored within the container until the fire suppressant is expelled. The container is generally filled with enough fire suppressant and/or propellant gas such that the vapor pressure within the container is sufficient to discharge the fire suppressant at somewhat cold temperatures. In other situations, the container may be exposed to relatively high temperatures, which may result in the vapor pressure within the container being somewhat high. This means that the container may be designed to have a wall that is thick enough and/or strong enough to contain this high amount of vapor pressure. This may result in the container being heavier and/or larger than the container might otherwise be.
In addition, conventional fire suppression systems may discharge fire suppressant quite differently depending on the ambient temperature when the discharge occurs. As mentioned above, the vapor pressure within the sealed container will generally be dependent on the ambient temperature. If the ambient temperature is too low when the discharge is triggered, the vapor pressure within the container may be insufficient to sustain a proper discharge of the fire suppressant. That is, some of the fire suppressant may be discharged with insufficient pressure to extinguish a fire. Additionally, at such low discharge pressures, the fire suppressant may evaporate before reaching discharge nozzles, adding further variability. Also, the pressure within the container generally decreases as the fire suppressant and/or the propellant gas exit the container, regardless of the ambient temperature.
Accordingly, there is a need for a fire suppression system that provides a relatively stable discharge pressure and allows for a smaller and/or lighter fire suppressant container.